Thought about this for a while. Different country, whole different ball game.
For one, no such thing as track insurance and our tracks (not high grade FIA spec) do not have huge run off. Have a big lose, and you'll meet concrete walls. That changes the criteria completely to what would I be prepared to lose, walk away and not care about. E9x/F8x would be too "good" as a dual-duty car, unless I could land and rebuild a total loss. No space to do that, yet.
Enter 86.
Something without ABS to get skills up would be cool. E36/S15/R33 etc. Spend more time fixing each one's specific problems than racing it though and panels while cheap if you look hard enough are surely NLA soon or already.
86 can be built to national spec for the 86 cup and some other smaller categories if I ever felt compelled to like compete with semi-pros/gentlemen racers in a couple of rounds. 15k/season, 30k for a prep'd car with spares. Can't really beat that here. Would be boring car to drive at COTA I bet though.
997.1 cup is 50-80k. They still make panels, shells for those. Unfortunately their boxes aren't cheap.